First flex the hip by passively pulling one thigh towards the abdomen.
Then extend the knee with the ankle plantarflexed, and the toes pointed.
Once reaching full knee extension, pull the toes towards the shin, reaching the heel away from the buttock.
Follow this by retracting the chin, flexing the neck and rounding the shoulders so that the head and shoulders come off the ground.
Return to the supine position by first returning the spine to neutral, and then by reversing the lower extremity movements.